Method of and means for investing denture models and patterns



June 24, 1930. E. E. DALTON er AL 1,767,351'

TTEnns IETHODOF AND IEANS FOR INVESTING IDENTURE MODELS AND PA Whaler/MaZZYa J' ingle v Amm] F'ld Oct. 7, 1927 June 24,1930. E. EIDAQLTQN Em1,767,351

muon or*4 Ann mms Fon mvss'rine DFN'x-URE u'oDsLs Ann PATTERNS" FiledOct. '7,` 1927 2 Sheets-Sheet 2 Patented June 241, 1930 UNITED STATESPATENT OFFICE .l ERNEST E. DALTON AND CHARLES J'. BINGLE, OF CHICAGO,ILLINOIS METHOD OF AND MEANS FOR INVESTING DENTUBE MODELS AND PATTERNSApplication filed October `7, 1927. Serial No. 224,749.

This invention relates to a method of and means for investing denturemodels and patterns.

Heretofore in investing-models and patterns of this sort, theinvestmenthas been commonly painted on the model and wax patl tern.This'investment painting process has ally been a matter of guess work,produced by building up the investment by the process of painting itupon the model or pattern. More than one mix is frequently required andthe matter of getting the investment well around the pattern and sprueattachments has presented a difficult problem.

Still further a casting of this sort must be relatively thin, as wellunderstood in the art and where the investment produces a rough-.

ness which requires any considerable grinding or finishing it is notinfrequent to grind through the casting or produce weakened portions orimperfections in endeavoring to produce the smoothness which is sodesired.

The object of the present invention is the provision of a generally im'roved method of and means for investing enture models and patterns toproduce a smoother investment, a better uniformity in the body andsurfaces of the investment and an investment of greater density.

More particularly the present invention provides a boxing device and forcondensing and confining the investment. The invent-ion eliminates roughsurfaces on the mold and the grinding of 'the surfaces of the casting maalso be eliminated, although it isfto be un erstoodthat the casting maybe ground or lfinished, if desired. Where there is any grinding orfinishing itis slight and any danger of grinding through the casting orweakening same is avoided.

-of Fig. 5;

ing' cavity;

The invention expedites the investing process, eliminates -thepossibility of voids or blow-holes and assures an investment which shallbe uniformly of required or sufficient thickness and without guess work.

The invention is particularly applicable to the formation of metal,usually gold or aluminum castings, but it is to be understood that theinvention is not limited to use in forming a casting or plate of anyparticular material, but may be employed wherever suitable or desired.

The invention is illustrated in the accompanying drawings, in which:

Fig. 1 is a top plan view of an illustrative castin model and patternthat may be employe in connection with the present inven- 1on; l Fig. 2is a section takenv on the of Fig. 1;

Fig. 3 lllustrates more or less diagram-` matically the step of applyingthe painting investment and simultaneously vibrating the casting modeland pattern to settle the investment and bring any air or other gases tothe surface;

Fig. 4 illustrates more or less diagrammaticall the next step in theprocess; ig. 5 is a top plan view of one form of boxing 'or coninin andcondensing device with substantially t e amount of the investmentmaterial which is first introduced and the casting model in placetherein;

Fig. 6 is a section taken on the ine 6--6 Fig. 7 is a sectional viewsimilar to Fig. 6 showing the boxing device substantially filled withthe investment material;

Fig. 8 is a view similar to Fig. 7 showing illustratively the step inthe process which follows the filling of the boxing device;

Fig. 9 is a sectional view of the invested model with the boxing deviceremoved.

Fig. 10 is a sectional view showing the invested model centered in -acentrifugal flask or casting ring with the outer or fin-- ishinginvestment applied and after introducing the gold or other metal intothe castl shaft lnected by wax sprue leads 12 eign material on thesurfaces Fig. 11'is a plan view of the nished casting with the metalcast in the sprue openings still in place;

Fig. 12 is a sectional view taken on the line 12-12 of Fig. 11; and

Fig. 13 is a view similar to Fig. 12 after removal of the metal andconnections cast in the sprue openings.

Referring to the drawings, the model designated at 5 may be of anysuitable or preferred form. These models are usually made of suitableplaster-like material from the dentists impression, as well understoodin the art. The particular details or material of the model, per se,form no part of the present invention. Sulliceit to say that 5designates any suitable model, thematerial and formation of which mayvary Widely.

The impressed plate 'forming surface 6 of the model 5 is provided with awax coating 8 of a thickness corresponding substantially to thethickness of the plate or casting. This waxed coating 8 is usuallypainted on with a suitable brush, as well understood, although this tooforms no part of the present invention and may vary widely. The waxcoating forms a wax pattern for forming the plate casting cavity and asuitable wax dental pattern 9 may be provided for forming the lingualcastin cavity, all as well understood in the art. n upright andpreferably centrally disposed sprue 10, preferably of wax or othersuitable material, is con- With the wax casting pattern for receiving,passing and distributing thegold, aluminum or other molten metal intothe plate casting cavities, as well understood.

By the rst step in our process the painting investment "material ispainted over the entire wax pattern, as by means of a suitable brush 14,as shown in Fig. 3. The painting process assures good,'close and uniformcontact of the investment material with the entire surface of thepattern and mold, if desired, and prevents a surface irregularities orany roughness in I#the surface of the investment along the pattern, suchas might be produced by oilysubstances or other forof the pattern. Inpainting the investment it paint the investment material well over thesurface of the attern and well around the attachment of t e sprue.

The painting investment is indicated at 15 in Fig. 3 and in applyingAthis painting investment 15 the model 5 is preferably vibratedsimultaneously witli the ainting on of this investment. This may e doneby placing the model upon a metal plate 16 and placing this plate 16upon the projecting 18 of a motor 20, as shown in Fi 3. When the motoris started the shaft 18 will vibrate the plat@l 16 which will settletheinvestment 15 and spread and rub the same vibration is desirable to buniforml over the surface of the wax pattern 8. bviously the motor shaft18 may be provided with eccentric or cam means for additionallyvibrating the plate 16. The

of the model with the application of the painting investment settlesythe same and brings any bubbles or gases to the surface, eliminating thepossibility of voids or blow-holes and assuring a smooth casting whichneed not be ground or which will at least require only a minimum ofgrinding or finishing. By vibrating the model simultaneously with theapplication of the investment 15, this application need not be as slowas heretofore and by means of this and the remainder of the techniquethis investment 15 may be applied liberally and without regard to theamount or uniformity f the thickness thereof.

By the next step in the process the investment material 22 which may besubstantially the same as the painting investment or any other desiredinvesting material is placed in a boxing device 23 up to say a level ofabout 1 inch and with the boxing device 22 laid upon the plate 16 uponthe motor'shaft 18 for vibrating the same, the model upon which theinitial investment material has been painted at is placed in the boxingdevice 5, as shown in Fig. 4.

The boxing device 23 is preferably of wax or other material that may beconveniently removed from the investment, as will be hereinafter pointedout. It has a closed bottom 25 provided with integral upstanding nibs 26for engaging the flat bottom surface of the model 5 and supporting samein proper position in the boxing device 23 and raised slightly above thebottom wall 25 thereof. Upstanding marginally from the bottom wall 25the boxin device 23 has the side walls 28 which may e rounded at 29 andflat or square at 30 to conform with the general contour of the model.It is to be understood, of course, that the particular shape orconfiguration of the boxing device may be varied as desired. The topofthe boxing device is open at 32 and this open top 32 is provided witha separate removable cover 34, which is also preferably of wax or othermaterial that may e readily removed from the investment. The cover 34has an upright sleeve or tubular projection 35. The sleeve or tubularprojection 35 ma be formed integral with the cov` er 34 and 1t definesan opening 36 for intro` ducingthe final portion of the rst investmentand the upper open end 38 of the upright sleeve 35 is adapted torecei-ve a Weight or suitable closure, as will be pointed out later foradditionally condensing the investment in the boxing device. Marginallythe cover 34 is provided with a depending flange 39 v which, when thecover is placed on the boxing A, ly .about the model.

tinuing to settle The boxing device 23 confines and condenses -theinvestment material 22 and the boxing device may be vibrated upon themotor shaft with the investment material 22 up to substantially thelevel shown in Fig. 4 before placing the model therein. This will settlethe investment and bring any lbubbles surface.' The model is'thencontinuing the vibration of the box the modelv is settled down intoposition upon the nibs 26,as shown in Fig. 6 and the investment material23 is settled and condensed uniform- Additional investment material 22is then introduced into the top of the box 23, the vibration upon themotor shaft 18, or in any other suitable 4manner conany gases or bubblesto the surface, as the investment is builtup in the boxing device. Thisproduces a smooth surfaced investment and an investment having greaterdensity and with its body and surfaces more uniform.

As the investment isbuilt up, in this` manner to or toward. the top ofthe box 23 the cover 34 is'placed upon the box. The upright sleeveportion 35 in addition to pro# 'viding material and for additionallycondensin the same receives the sprue 10. The ladditional investmentmaterial may be then lintroduced thru the upright sleeve portion 35 upto. the top thereof, the vibration of the boxing device continuing tosettle the investment and bring any bubbles or gases to the surface asit is introduced andto confine and condense the same uniformly anddensely about the model.

When the boxing device has been filled up to the top of the tubularprojection 35 an additional amount of investment placed over the top ofthe opening 38 so that the investment will project therefrom and,

f then the investment in the boxing device may any be additionallycondensed by placing a weight or closure 45 over the opening 38, asshown in Fig. 8. The closure 45 may be flexible so that it may bepressed down by the f hand to additionally condense the investment Yalthough material within the boxing device,

other suitable condensing application may be imparted. Thissubstantially completes the technique and the boxing and condensingprocessof the present invention, and wey find that a smoother investmentis produced together with a, better uniformity in the body and surfacinvestment is of greater density and surface w irregularities androughness are avoided.

We nd that an exceedingly smooth' casting v .is produced and thatgrinding and finishing may be eliminated or where desired is slight andwithout danger of grinding through or vweakening; the casting. When theinvestment 23 has set and lhardened the wax strucvention,

the investment and bringv may bel s of the investment. The

ture of the boxing device permits this to be expeditiously andconveniently peeled off. This is another important aspect of theinalthough it `is to be understood thatl the boxing device may be ofother material and it may be formed for removal from the investmentwithout peeling it off or destroying the boxing device. In this mannerthe boxing device would be adapted for re-use although thisv isnotdesirable and we prefer to peel it olf and destroy itafter vone use.

After the boxing device 23 is removed the investment is centered in asuitable metal flask or castin ring 50, as shown in Fig. 9 and the ringis lled with the casting or outer investment 52 AWhi'ch is then allowedto set. These casting rings are usually made of two pieces and providedwith lugs 53 which lock the ring in the centrifugal casting machine,

as well understood in the art. The features of investing the investmentin the ring 52 apply particularly to Wherethe denture is -Ployedforintroducing further investment After the investment 52 has setthe'investment may be dried out to burn out the wax sprue 10 andconnctions 12 in the usual or any suitable manner. This is frequentlydone by. `placing the investment on aradial burner with the sprue holedown and when the gas is turned on it burns out the Wax inlays andfrees'the investment of any Water. Any other suitable or-preferredmanner of removing 'the wax may, of course, be `eniployed. 1' i Incentri'fugallycasting the same after the investment 52 has set andhardened suficiently the ring 50 is placedin the centrifugal castingmachine vand the gold or other'` molten material is introduced throughthe sprue cavity 54 and'flows in and ills the casting cavities 56 and57' andthe sprue connection cavities 55. The resulting casting isdesi'gf nated at 58, it consists of the plate portion 59, l

' connectionsA 62 extended may be finished as desired.

Wherel we use the term model in the appended claims we intend itto'apply to the model and pattern and a painting of the main body of themodel or the pattern portion only is tobe considered a paintingof themodel. f L

We also intend'the term model to cover any dental model or patternWhether for a complete or partial denture, an inlay or 'anyoralrestoration.

inl

, ing an open top and a cover removably fitting the top of said box andprovided with a tubular projection opening into the interior of the box,said boxing device being formed of a material that may be peeled off 'ofthe investment.

3. As an article of manufacture, a boxing device formed to receive adenture model, said boxing device being adapted to confine the investingmaterial upon the model and of a material which may be peeled off of theinvestment..

4. As an article of manufacture, a boxing device for dental investmentformed of wax and adapted to receive and confine the investment upon themodel.

5. As an article of manufacture, a boxing device for dental investmentcomprising a box having an open top and a removable cover having adepending marginal flange adapted to lit over the upper marginal edge ofsaid box and having a tubular wax projection opening into the box.

6. As an article of manufacture, a dental boxing device includin a boxpart and a cover part and rovidelwith a tubular projection on one o saidparts and openingl into the interior of the boxing device.

an article of manufacture, a dental boxing device adapted to receiveinvestment material and a dental model for molding and confining theinvestment material upon the model and means within said boxing deviceand independent of the investment material for spacing the model fromthe bottom of the boxing` device.

8. As an article of manufacture, a dental boxing device adapted toreceive investment material.. and a dental model for molding andconfining the investment material upon the model and means within saidboxing device and independent of the investment material for spacing themodel from the bottom of the boxing device, said means comprisingupstanding nibs on the interior of the bottom Wall of the boxingydevice.

9. As an article of manufacture, a dental boxing device formed ofreceive investment material and' a dental model for molding andconfining the investment material upon the model and integral wax nibson the interior of the bottom wall of wax and adapted to- 11. A boxingdevice comprising a box formed to receive a denture model and having anopen side and ting the open side of said box, said closure having anopening providing communication from the exterior of said box into theinterior of the box.

12. As an article of manufacture, a noxing device cover comprising aclosure portion and a tubular projection formed integrally 'of Wax.

In Witness whereof, We hereunto subscribe our names this 3rd day ofOctober, 1927.

' ERNEST E. DALTON. CHARLES J. RINGLE.

a closure removably itv

